How do plants cause mechanical weathering?

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Plants can cause mechanical weathering by sprouting and growing in soil that has collected in the cracks of a rock. As the plant grows, the roots extend and spread the crack until the rock eventually breaks.

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Any plant seed that begins to grow inside a crack or fissure in a rock has the potential to cause mechanical weathering. Even plants with small root structures can eventually crumble a rock. Trees have much larger root systems and can break apart even large rocks and rock structures over time. These seeds may arrive in a variety of ways that range from birds carrying and dropping them to being blown by the wind or traveling via water.

Mechanical weathering is also referred to as physical weathering and occurs anytime there is a physical breakdown caused by animals, plants, water, salt or other factors. Mechanical weathering is what causes rocks to crumble or break. This type of weathering is constantly ongoing in nature, but is it generally a slow process that occurs over time. Nature is in a constant state of flux.

Other examples of mechanical weathering function in similar ways. Fluctuating temperatures can cause stress in pre-existing cracks that eventually cause the rock to break. Water collected in the cracks can freeze and thaw repeatedly, enlarging the cracks over time.

Related Questions

There are four types of physical forces that cause physical weathering: frost action, temperature fluctuation, abrasion and salt crystal growth. Physical weathering is a process that causes rocks to weaken, disintegrate and eventually break down completely over time.

Desertification causes a high-risk of crop failure, low economic returns on crops, a build-up of salt in the soil and the accidental burning of semiarid vegetation. This process turns usable desert land into unusable land due to poor land management.

Some of the abiotic factors found in a tropical rainforest are high temperatures, heavy rainfall, poor nutrient content in soil and sunlight that is found primarily at the tree canopy level while remaining limited at ground level. Because of the heavy overhead canopy, the forest floor may receive as little as 2 percent of the sunlight. Precipitation, which is a significant abiotic factor in a non-aquatic ecosystem, can range between 98 and 177 inches annually in a tropical rainforest.